Beside these changes, the Developer Dashboard can now be extended by injecting custom JavaScript code into the developer dashboard window.

Two steps are necessary to achieve this:

Custom JavaScript code, which interacts with the developer dashboard DOM, has to be added to a script file that can be accessed from the Developer Dashboard page. E.g. by placing the script file into the _layouts/15 directory

The custom script file(s) have to be registered to be loaded into the Developer Dashboard page.

Below is a short example, which hides the ULS tab in the Developer Dashboard. This example also shows how to use jquery within the Developer Dashboard.